Many types of orthopedic devices include hinges that serve to support joints, and control and limit joint movements. These joints include the knee, elbow, shoulder, hip, ankle and wrist joints.
The knee joint, although frequently considered a hinge joint, comprises two joints, lateral and medial, between the femur and tibia, and one arthrodial joint between the patella and femur. The primary movements of the knee comprise flexion, i.e., rearward rotational movement of the tibia relative the femur, and extension, i.e. forward rotational movement of the tibia relative the femur.
The flexion and extension movements of the knee joint are not simply pivotal movements about a fixed axis. During flexion, the axis around which movement takes place shifts backward, and during extension it shifts forward. This is different from a more typical hinge joint, such as an elbow, where the axis of rotation does not shift. As full extension is reached, the tibia is rotated inward or rearward and the joint in effect is disposed in a “locked” position with the ligaments taut. This gives the joint greater stability in the extended position. As flexion is initiated, the tibia initially lowers or moves downwardly with small external rotation of the tibia unlocking the joint and subsequently the tibia rotates or rolls about the joint to full flexion. Accordingly, the initial unlocking of the knee joint during flexion precedes actual full rotation of the knee.
Because of the complexity associated with knee movement as described above, a knee brace hinge mechanism must be able to simulate the movements of the knee. The incorporation of such hinge mechanism is crucial, as the knee brace must optimally support the knee joint of its user.
In the context of post-surgical applications, the requirement for such simulation of the knee joint is essential in order to rehabilitate and prevent re-injury of an injured knee joint. Additionally, the hinge mechanism should also be able to control the range of knee joint flexion and extension so that the knee is not reinjured due to hyperextension or flexion. As the optimal range of knee joint motion may vary between users and change during the progress of rehabilitation, the knee brace hinge mechanism used in conjunction with such surgical applications should further be adjustable to correspond to the particular motion range of the user's leg.
In recognizing the need for an effective post-surgical knee brace, various types of hinge mechanisms have been incorporated into known knee braces for post-surgical applications. However, most conventional hinge mechanisms typically fail to provide the precise simulation of knee joint movement or control the range of knee joint motion. Such deficiencies inevitably decrease the likelihood of the user's knee joint from being properly rehabilitated after surgery. Further, some known knee brace hinge mechanisms fail to possess sufficient adjustability so as to quickly and easily provide the optimal set range of knee motion depending upon the current user's needs and rehabilitation progress.
In view of the shortcomings of conventional knee brace hinge mechanisms; there exists a substantial need in the art for a hinge system that can closely simulate the motion of the knee joint while regulating the range of its flexion and extension. More specifically, it is desirable to provide a hinge system that can be easily and quickly adjusted so as to provide a variable, optimal range of knee joint flexion and extension for the particular need of its user.
Many contemporary knee braces fail to provide the precise simulation of knee joint movement or have comprised relatively heavy, bulky apparatus, thereby detracting from the user's athletic endeavor. Further, known designs fail to possess sufficient structural integrity to prevent re-injury of the knee joint as may be occasioned by impact to the knee joint during physical sport endeavors.
The features of the present invention are provided in recognition of the need for orthopedic braces and hinges components for use that are streamlined, low profile, and easy to adjust while effectively supporting joints, and controlling and limiting joint movement. This recognition is realized with the invention described hereinafter.